在SpringMVC中，理解并操作：重置风格与form表单的CURD实践

CRUD
c:create创建
r:retieve:查询
u:update：修改
d:delete：删除

rest

/emp/1 get 代表查询id为1的员工
/emp/1 put 代表修改id为1的员工
/emp/1 delete 代表删除id为1的员工
/emp   post 代表新增员工
/emps  get  代表查询所有的员工

/indexemp.jsp --->emps请求--->转发到empList.jsp展示所有员工数据

添加：
	empList.jsp中点击添加员工，--->查询所有的部门信息要展示在页面-->添加页面（addEmp.jsp）
	-->输入要添加的数据-->点击保存--->控制器接收请求处理保存数据--->保存完成--->继续回到首页

修改：
	在页面点击修改--(查询要修改的员工信息，放到域对象中，修改页面显示数据/emp/1 get)
	->员工的修改页面（editemp）--->输入要修改的数据，点击修改按钮，发送请求/emp/1 put 
	-->修改员工--->员工列表页面
	
	删除：
		在页面点击删除-->发送删除请求（/emp/1 delete）-->删除-->来到主页面

package com.tanzhou.controller;

import java.util.Collection;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;

import com.tanzhou.dao.DepartmentDao;
import com.tanzhou.dao.EmployeeDao;
import com.tanzhou.domain.Department;
import com.tanzhou.domain.Employee;

@Controller
public class EmployeeController {
	@Autowired
	private EmployeeDao employeeDao;
	@Autowired
	private DepartmentDao departmentDao;
	/**
	 * 查询所有的员工
	 */
	@RequestMapping("/emps")
	public String getEmps(Model model){
		Collection<Employee> emps = employeeDao.getEmployees();
		model.addAttribute("emps", emps);//存到request域对象中
		return "empList";
	}
	
	//	public Employee(Integer id, String name, String email, Integer sex, Department department) {

	@RequestMapping("/addpage")
	public String addpage(Model model){
		Collection<Department> depts = departmentDao.getDepartments();
		model.addAttribute("depts", depts);
		model.addAttribute("employee", new Employee());
		return "addEmp";
	}
	
	@RequestMapping(value="/emp",method=RequestMethod.POST)//
	public String addEmp(Employee employee){
		System.out.println(employee);
		employeeDao.save(employee);//模拟保存
		return "redirect:/emps";//添加之后直接重定向到查询员工的请求
	}
	//<a href="${pageContext.request.contextPath}/emp/${emp.id}"></a>
	@RequestMapping(value="/emp/{id}",method=RequestMethod.GET)
	public String getEmpById(@PathVariable("id")Integer id,Model model){
		//根据id查询员工
		Employee employee = employeeDao.getEmployee(id);
		model.addAttribute("employee", employee);
		//查询所有部门
		Collection<Department> dept = departmentDao.getDepartments();
		model.addAttribute("depts", dept);
		return "editemp";
	}
	
	//修改员工
	@RequestMapping(value="/emp/{id}",method=RequestMethod.PUT)
	public String updateEmp(@ModelAttribute("employee")Employee emp){
		System.out.println(emp);
		employeeDao.save(emp);
		return "redirect:/emps";
	}
	@ModelAttribute
	public void modelAttribute(@RequestParam(value="id",required=false)Integer id,Model model){
		//先根据id查询员工
		if(id!=null){
			Employee employee = employeeDao.getEmployee(id);
			model.addAttribute("employee", employee);
		}
	}
	//删除
	@RequestMapping(value="/emp/{id}",method=RequestMethod.DELETE)
	public String deleteEmp(@PathVariable("id")Integer id){
		//删除
		employeeDao.deleteEmployee(id);
		return "redirect:/emps";
	}
}

package com.tanzhou.dao;

import java.util.Collection;
import java.util.HashMap;
import java.util.Map;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;

import com.tanzhou.domain.Department;
import com.tanzhou.domain.Employee;
@Repository
public class EmployeeDao {
	@Autowired
	private DepartmentDao ddao;
	
	private static Map<Integer,Employee> map = null;
	//	public Employee(Integer id, String name, String email, 
//	Integer sex, Department department) {
	static{
		map =  new HashMap<>();
		map.put(1, new Employee(1,"王A","WA@QQ.com",1,new Department(1,"研发部")));
		map.put(2, new Employee(2,"王B","WB@QQ.com",2,new Department(2,"市场部")));
		map.put(3, new Employee(3,"王C","WC@QQ.com",1,new Department(3,"策划部")));
		map.put(4, new Employee(4,"王D","WD@QQ.com",2,new Department(2,"市场部")));
		map.put(5, new Employee(5,"王E","WE@QQ.com",1,new Department(1,"研发部")));

	}
	private static Integer initid = 5;
	/**
	 * 新增或修改
	 * 如果传入对象有id，代表修改
	 * 如果传入对象没有id，代表新增
	 * @param emp
	 */
	public void save(Employee emp){
		if(emp.getId()==null){
			emp.setId(initid++);
		}
		emp.setDepartment(ddao.getDepartment(emp.getDepartment().getDid()));
		map.put(emp.getId(), emp);
	}
	/**
	 * 获取所有的员工
	 * @return
	 */
	public Collection<Employee> getEmployees(){
		return map.values();
	}
	/**
	 * 根据id查询员工对象
	 * @param id
	 * @return
	 */
	public Employee getEmployee(Integer id){
		return map.get(id);
	}
	/**
	 * 根据id删除员工
	 * @param id
	 */
	public void deleteEmployee(Integer id){
		map.remove(id);
	}
}


package com.tanzhou.dao;

import java.util.Collection;
import java.util.HashMap;
import java.util.Map;

import org.springframework.stereotype.Repository;

import com.tanzhou.domain.Department;
@Repository
public class DepartmentDao {

	
	private static Map<Integer,Department> map = null;
	
	static{
		map =  new HashMap<>();
		map.put(1, new Department(1,"研发部"));
		map.put(2, new Department(2,"市场部"));
		map.put(3, new Department(3,"策划部"));
	}
	
	//获取所有部门信息
	public Collection<Department> getDepartments(){
		return map.values();
	}
	
	//根据部门编号查询对应的部门
	public Department getDepartment(Integer did){
		return map.get(did);
	}
}